EMC-filter

ABSTRACT

The invention which relates to an EMC filter (1) addresses the problem of specifying an EMC filter (1) that is simple of structure, cost-effective and temperature resistant. This problem is resolved thereby that the core of the choke (4, 5) is comprised of one or two core parts (10), that at least one first planar or convex heat transfer area (23) is located on an outside of the core and that the core with this first planar or convex heat transfer area (23) is disposed on a housing (12) of the refrigerant compressor, wherein the housing (12) in the region of the first planar or convex heat transfer area (23) is implemented planar or concave.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority from German Patent Application No.102017109321.4 filed May 2, 2017, which is hereby incorporated byreference in its entirety.

FIELD OF THE INVENTION

The invention relates to a passive EMC filter having at least one chokewith a core and several capacitors.

BACKGROUND OF THE INVENTION

In electronic componentry, in which switching processes are carried outwith electric voltages or currents, interferences are generated as aconsequence of these switching processes due to the generated electricalpulses with the associated emission of interference signals. Theseinterferences can propagate as electromagnetic waves conductively acrosslines as well as also radiatively through free space.

The capability of a technical device not to subject other devices tounintentional or accidental electric or electromagnetic effects or besubjected to same by other devices, is referred to as electromagneticcompatibility (EMC).

To avoid or minimize the propagation of such interferences, prior artproposes equipping this componentry with a filter unit, a so-called EMCfilter or network filter. It is also known to take measures forshielding or screening the electronic componentry in order to avoidimpacting the correct functions of other electronic components ordevices through interference signals of too high an amplitude level.

Such EMC filters are also utilized in hybrid and electric motor vehiclesfor example. The present description refers, in particular, to the useof EMC filters in electrical refrigerant compressors of motor vehiclesin order to ensure that specified electromagnetic limit values areobserved.

The magnitudes of such interference signals that must be observed by adevice in circulation are established in EMC standardizations associatedwith this device and described by means of limit values that must beobserved.

Known in this context are for example the so-called ECE provisions whichinclude a catalog of international agreements on uniform technicalregulations for motor vehicles as well as parts and equipment objects ofmotor vehicles. The area of radio interference suppression is treated,for example, in ECE R10, which has to be followed in future developmentsand which will result in further decrease of the permissibleinterference radiation.

Electromagnetic interference radiation is also generated in theoperation of electric inverters that actuate an electric motor and thusswitch currents of high amplitude. Such an inverter is utilized, forexample, in actuating a motor in an air conditioner compressor of amotor vehicle.

A known solution for suppressing the interference radiation on electricor electronic components is the use of a passive EMC filter which isinserted, for example, in a feed line of the operating voltage. Suchpassive EMC filters are conventionally realized with the aid of passivecomponents such as capacitors, coils and resistors which are connectedin known, suitable manner and consequently generate the desired filtereffect.

Based on the type of interferences to be filtered by means of an EMCfilter, the distinction is made between common mode interference anddifferential mode interference. The interference spectrum to be filteredby the EMC filter is in practice comprised of the sum of both superposedinterference components.

The type, structure and especially the voltage level of an inverter, forexample for an electric refrigerant compressor, determine which of thetwo interference components is predominant and, consequently, which ofthe two interference components must be filtered more strongly.

In the case of inverters for refrigerant compressors that are operatedin a voltage range of approximately 48 V, primarily differential modeinterferences occur due to the low operating voltage and thesimultaneously high arising currents in a range of, for example, 100 Ato 200 A.

Prior art proposes filtering such differential mode interferences byemploying so-called chokes in combination with capacitors in a passiveEMC filter. For this purpose, for example, in each feed line of theinverters HV+ and HV− one choke L₁ and L₂ each is inserted andcorresponding capacitors C₁ and C₂ are disposed in feed lines HV+ andHV− before and after the chokes L₁ and L₂. In addition, in passive EMCfilters a third capacitor C₃ is connected between the input line HV− andground potential and a fourth capacitor C₄ between the input line HV+and ground potential.

Chokes as coils or inductors are known for limiting currents in electriclines, for the intermediate storage of energy in the form of theirmagnetic field, for impedance matching or for filtering. Such chokes arefrequently inserted into a voltage feed line of an electric component.To enhance their so-called inductive reactance or reactance, chokesfrequently include a soft magnetic core. It is known to utilize as thesoft magnetic materials ferromagnetic substances that can be readilymagnetized in a magnetic field.

Through the chokes L₁ and L₂, disposed in the feed lines HV+ and HV− ofthe inverter, flows the maximally possible input current of the inverterwhich can be in the range of 150 A and more, and these chokes mustconsequently be appropriately dimensioned for this current load.

This high interference-superimposed input current engenders in chokes L₁and L₂ a magnetic field. In contrast to so-called common mode chokes, inwhich, due to the counter directed windings of the two choke windingsdisposed on a common core the magnetic fields of the input currents inthe common core cancel each other out, this positive effect does notoccur in the case of differential mode chokes.

It is therefore technically not sensible to construct differential modechokes, or chokes with which differential mode interferences are to bereduced, with their windings on a common core since the magnetic fieldsof both windings in the core are superimposed and so-called saturationeffects occur earlier in such a configuration.

Due to the relatively high input currents in a range equal to or greaterthan 150 A at an operating voltage of, for example, 48 V, in the coresof the chokes or differential mode chokes considerable core losses occurwith a power loss of several watt. These losses are determined by theproperties of the core material utilized and the winding structure.

This power loss leads to heating of the core of the chokes whereby, inturn, the core properties are changed. It is especially disadvantageousthat with the heating of a ferrite core its magnetic properties changesuch that the maximal flux density decreases before the occurrence ofsaturation effects.

According to prior art it is customary to operate, for example, aferrite core of a choke of a passive EMC filter without a coolingsystem. Due to the heating, the components of such an EMC filter,especially the choke, are overdesigned in order to ensure reliable,interference free operation of the inverter as well as othercomponentries in the proximity of the inverter.

It can, alternatively, also be provided that air is conducted throughthe core of a choke or of a transformer, which is also referred to asactive air cooling.

It is, in addition, also known to move a coolant through the core of achoke or a transformer, which is also referred to as active liquidcooling.

In the field of power electronics there is a trend toward higher powerdensities. In order to be able to achieve these increased powerdensities, the systems need to be designed optimally with respect totopology and semiconductor selection. Furthermore, the installationvolume of the components is to be decreased. However, the decreasingvolume in connection with a reduced surface impedes the possibilitiesfor adequate cooling of such components.

A solution for cooling such components is found in the document “CoolingConcepts for High Power Density Magnetic Devices” by J. Biela and J. W.Kolar athttp://www.pes.ee.ethz.ch/uploads/tx_ethpublications/biela_PCC07.pdfwhich consists in utilizing a heat pipe as heat exchanger, wherein theheat pipe, utilizing the heat of evaporation of a medium, can transporta heat quantity, for example, from a first end of the heat pipe to itssecond end.

However, such cooling methods can only be implemented in an electricrefrigerant compressor of a vehicle, such as for example a motorvehicle, using technically complex and installation and cost intensivemeans.

OBJECTS OF THE INVENTION

The objective of the invention comprises specifying an EMC filter whichis of simple structure as well as cost-effective andtemperature-resistant.

SUMMARY OF THE INVENTION

The objective is achieved through a subject matter with thecharacteristics according to the invention described herein.

The EMC filter is comprised of several passive components, such as coilsand capacitors.

In a conventional circuit configuration of a passive EMC filter, chokesare disposed in the feed lines HV+ and HV− of an inverter. In addition,capacitors or capacitances are provided between the feed lines HV+ andHV− before and after the chokes as well as in each case between groundpotential and feed lines HV+ and the feed line HV−.

Due to the high currents, the chokes provided in such passive EMC filterare implemented with a bus bar, for example comprising copper or acopper alloy, a so-called copper bus bar, as the electrical conductor.It is provided to hold the number of requisite windings for the chokesvery low through suitable selection of the magnetic material for thecore of the choke.

A specific implementation provides implementing the windings in the formof a copper bus bar curved in the shape of a U that is received in aferrite core. The winding used in this implementation consequently has awinding number of only one winding.

A unitary ferrite core can be provided with any chosen body, such as forexample an annulus or a toroid. To simplify the fabrication of such achoke, it is also provided to fabricate the core of the choke of atleast two parts. In this way it is, for example, possible, using twoC-shaped cores or ferrite cores, to place the previously curved U-shapedcore or copper bus bar into the first of the C-shaped core and to coverit with the second C-shaped core and in this way obtain a finished corethat encompasses the winding or the bus bar. Such a core can bedeveloped in a shape that is, for example, cuboid or annular.

A partitioning of the core, for example onto four subcores, which, afterassembly, yield the required core of the choke, is also feasible.

With the restriction that the core comprises at least one outer planaror convex area, which in the following will be denoted as heat transferarea, the outer shape can be devised freely. For example, the core canhave the shape of a cube, a cuboid or also a sphere with a planar area.Alternatively, a subregion of the surface of the sphere with a convexsurface contour can also be selected as the heat transfer area.

It is furthermore advantageous for the core to comprise two outer planaror convex areas, wherein these are preferably disposed oppositely suchthat, for example the two planar areas are oriented parallel to oneanother on the outer wall of the core.

The invention provides disposing the core of the choke with the, or oneof the, planar implemented heat transfer areas on a housing of arefrigerant compressor that, in the region of the heat transfer area ofthe core, has a planar-shaped surface and in this way drain the heatfrom the core into the housing. This placement on the outer wall of thehousing of the refrigerant compressor is carried out such that betweenthe core and the housing low resistance to heat transfer developswhereby the heat can be better dissipated from the core. As lowresistance to heat transfer is viewed a value of 10 kelvin per watt orless.

The surface of the housing, which can be produced using a castingprocess and consequently has a rough surface, can be milled, rubbed orground level. To improve the heat dissipation from the core into thehousing of the refrigerant compressor, a thermally conductive paste, athermally conductive mat or a thermally conductive pad, such as aso-called “gap pad”, can additionally be disposed between the heattransfer area of the core and the housing.

Such gap pads, also known as thermal interface or thermally conductivematerial and intended to improve the heat transfer between two surfaces,can be adherent on one or both sides and thus enable a sound andreliable securement of the core on the housing. It is furthermorefeasible to compensate by means of a gap pad any unevenness or surfaceroughness. As the material for a gap pad can be utilized for example afilled, thermally conductive polymer on rubber coated glass fibermaterial which has a thermal conductivity of 1.0 W/mK for example.

These properties of a gap pad ensure improved heat transfer between theheat transfer area of the core and the housing even in the case ofoccurrences of tolerances of manufacturing processes, for example withrespect to the surface quality of parts. Moreover, through the gap padthe vibration resistance and the tolerance compensation of the structureis improved. Consequently, it is ensured that under vibration thecomponents cannot vibrate freely.

If a core with a convex heat transfer area is utilized, it is providedthat the housing of the refrigerant compressor in the region of theconvex heat transfer area is concave and consequently the contour of thesurfaces of core and housing are matched to one another in the region ofthe heat transfer area. This matching enables good heat transfer of theheat from the core into the cooled housing of the refrigerantcompressor.

In an implementation of the invention it is provided that a core,comprised for example of two halves, of a choke of an EMC filter isdisposed with its first planar or convex heat transfer area on a housingof a refrigerant compressor. A gap pad is optionally disposed betweenthe heat transfer area and the housing. Provided for the safe securementof the core is a bracket which, in the case of a cuboidal core, isimplemented for example in the shape of a U and disposed over the coreand which is secured with its ends on the housing of the refrigerantcompressor. This securement can be accomplished by means of an adhesiveor by means of suitable plate washers to receive securement means, suchas screws, bolts or adjusting pins. These securement means are connectedwith the housing and consequently secure the bracket.

If a core of different shape is utilized, the bracket is correspondinglyadapted to the shape used.

After it has been bolted on, the bracket presses the core firmly againstthe housing of the refrigerant compressor through which flows a coolant.This coolant is utilized in the generation of the refrigerating capacityin the arrangement of the refrigerant compressor.

In the case in which the core is equipped with two opposing planarand/or convex heat transfer areas, between the second heat transferarea, facing away from the housing of the refrigerant compressor, andthe bracket a thermally conductive paste or a gap pad can also beinserted. In this case the heat on the second heat transfer area can bedissipated via the thermally conductive paste or the gap pad into thebracket comprised of a thermally conductive material and be conducted tothe housing across the bracket. Therewith the core can be cooled fromtwo sides.

The structural unit, which comprises the core of the choke, the bracket,the U-shaped curved bus bar of copper or a copper alloy as well as acircuit board to receive the electrical and electronic componentsnecessary for the inverter, can be encompassed or covered by a coveringor a cap. In this way a volume is created on a housing wall of therefrigerant compressor and this structural unit is protected againstpenetrating dirt or moisture.

In an alternative implementation of the invention it is provided that acore, comprised of two halves for example, of a choke of a passive EMCfilter is disposed with its first heat transfer area on a housing of arefrigerant compressor. Between the heat transfer area and the housing agap pad is optionally disposed.

In this case a sound and reliable securement of the core on the surfaceof the housing is achieved thereby that the core is provided with twoopposing heat transfer areas. It is provided that the first heattransfer area is placed on the housing. The second heat transfer area isin contact on the covering or cap. The core is consequently clampedbetween the housing and the covering or cap. In this case a thermallyconductive paste or a gap pad can also be provided on the heat transferareas in order to enable better heat dissipation through lowerresistance to heat transfer. In this example the heat transfer areas canalso be implemented such that they are planar or convex, with thesurface of the housing or the cap being implemented planar or concave inaccordance with the surface contour of the core in the region of theheat transfer area. The implementation of a core with a first planar anda second convex heat transfer area or conversely, is also conceivable.

The covering or cap is fabricated of a thermally conductive material,such as a metal, and can be secured to the housing of the refrigerantcompressor by means of bolts or fasteners.

In this implementation the heat can also be drained from the core acrossthe two heat transfer areas. The heat can therewith, on the one hand, bedissipated directly into the housing and, on the other hand, across thecap to the housing of the refrigerant compressor.

The advantages of the invention, consequently, reside in a greater loadcarrying capacity of the filter core of the choke of a passive EMCfilter. In addition, savings of the required installation space andcosts are achieved.

Further details, characteristics and advantages of implementations ofthe invention are evident in the subsequent description of embodimentexamples with reference to the associated drawing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1: an exemplary circuit configuration of a passive EMC filteraccording to prior art,

FIG. 2, 2 a: a core, comprised of four parts, of a choke,

FIG. 3: a first embodiment of the invention, and

FIG. 4: a second, alternative embodiment of the invention.

DETAILED DESCRIPTION

FIG. 1 shows an exemplary circuit configuration of a passive EMC filter1 according to prior art, which is connected to an inverter 2. The EMCfilter 1 includes an input 3 at which, for example a voltage of 48 V canbe applied, and comprises the chokes L₁ 4 and L₂ 5 disposed in feedlines HV+ and HV−. While the first capacitor 6 denoted C₁ is disposedbetween lines HV+ and HV− directly at the input of the passive EMCfilter 1 and before the chokes L₁ 4 and L₂ 5, the second capacitor 7,denoted C₂ is disposed after chokes L₁ 4 and L₂ 5 at the input ofinverter 2.

The third capacitor 8 denoted C₃ is disposed between line HV− and groundpotential. The fourth capacitor 9 denoted C₄ is disposed between lineHV+ and ground potential.

In this known circuit configuration on a housing 12 a core, disposedaccording to the invention on a housing 12 of a refrigerant compressor,can be found in the first choke 4 and optionally also in the secondchoke 5.

In FIGS. 2 and 2 a is depicted a core, comprised of four parts, of achoke 4 or a choke 5 from FIG. 1. The core could alternatively also becomprised of two parts.

In FIG. 2 shown on the left the core with its four core parts 10 isdepicted after assembly and encompasses the bus bar 11 of copper whichrepresents the winding of choke 4 or choke 5.

On the right of FIG. 2a the two upper core parts 10 are depicted afterthey have been raised. It can be seen that the core parts 10 areimplemented in C form and through this specific form enable receivingthe bus bar 11 having a rectangular cross section. The core parts 10 inthe assembled state of the core are firmly secured in their position bysuitable, not shown, means.

In the core depicted in FIG. 2 a first planar heat transfer area 23 isdeveloped on the undersurface of the core. A second planar heat transferarea 23′, oriented parallel to the first heat transfer area 23, isdeveloped on the upper surface of the core and is indicated in FIG. 2 bymeans of simple hatching.

FIG. 3 shows a first embodiment of the invention. Into a housing 12 of arefrigerant compressor a coolant 13 is introduced which is completelyenclosed by the housing 12. Housing 12 is produced of a metallicmaterial, for example as an injection molded part, and has good thermalconductivity.

On a surface 14 of housing 12 a core is disposed, comprised of twoC-shaped core parts 10, of a choke 4, 5 of a passive EMC filter 1. Forthe safe securement of the core with its first planar heat transfer area23 on the planar surface 14 of housing 12 and for a firm coherence ofthe core parts 10, a U-shaped bracket 15 is to be disposed. This bracket15 can be adhered at its ends to the surface 14. Alternatively, the endsof the bracket 15 can be implemented with plate washers 16 having holesthrough which the plate washers 16 of the bracket 15 can be bolted tothe housing 12.

The core is consequently connected with its second planar heat transferarea 23′ to the bracket 15 such that it is thermally conductive.

It is, alternatively, feasible to dispose the core with its first convexheat transfer area 23 on a concave surface 14 of housing 12 and, for afirm coherence of the core parts 10, to dispose a bracket 15 formedcorresponding to the surface of the core. This implementation of thecore with a convex surface in the region of the heat transfer area 23 isnot shown in FIGS. 1 to 4.

FIG. 3 shows in sectional representation the core as well as the bus bar11 extending through the core. In the example in FIG. 3, in which thecore has a rectangular opening, the bus bar 11 is implemented with arectangular cross section area. It is understood that the cross sectioncan also have a different shape, such as a square area, an n-gonal areaor a circular area and be adapted to the opening of the core. The endsof the windings of the choke, also of the bus bar 11, extending upwardlyin FIG. 3 are electrically connected to the circuit board 18 of theinverter. Such a connection can be implemented for example as a bolt ora solder connection. On this multi-layer circuit board 18 the capacitors6, 7, 8 and 9 that belong to the passive EMC filter 1 can be disposed.In addition, on the, for example, multi-layer circuit board 18 thecomponents associated with the inverter 2 are disposed.

The described elements can be covered by means of a cap 19 and thus canbe safely placed against penetration of dirt and moisture.

As is intended to be shown by the wavy arrows, the heat 20 in the lowerregion of the core can drain directly, or be dissipated across athermally conductive layer 21, to the housing 12 cooled with coolant 13.Such a thermally conductive layer 21 can be a thermally conductivepaste, a thermally conductive adhesive or a gap pad.

In the upper region of the core the heat 20 can be dissipated across thebracket 15 to the housing 12. In this way improved cooling of the coreof a choke 4, 5 in a passive EMC filter 1 is achieved. This improvedcooling serves for maintaining parameters which ensure the reliablefunction of the choke 4, 5 and consequently of the EMC filter 1. Throughthe improved cooling, in addition, the overdesigning of structuralparts, in particular of the choke 4, 5, can be dispensed with, whichresults in savings of costs and materials.

In FIG. 4 an alternative second embodiment of the invention is shown. Inhousing 12 of the refrigerant compressor a coolant 13 is introducedwhich is completely enclosed by housing 12. Housing 12 is fabricated ofa metallic material, for example as an injection molded part, and hasgood thermal conductivity.

On a surface 14 of housing 12 a core, comprised of two C-shaped coreparts 10, of a choke 4, 5 of a passive EMC filter 1 is disposed. For thesafe securement of the core with its first planar heat transfer area 23on the planar surface 14 of the housing 12, a cap 19 is provided whichis placed onto the edge of the housing 12 and securely closes off thevolume in which the choke 4, 5 as well as the circuit board 18 ofinverter 2 are disposed.

The secure hold of the core is achieved thereby that the first planarheat transfer area 23 is in contact on housing 12, while the secondplanar heat transfer area 23′, located parallel to the first heattransfer area 23, is in contact on a planar inner wall of cap 19.

Stated differently, the core is firmly clamped between the housing 12and the cap 19.

In this embodiment it is also provided to insert a thermally conductivelayer 21, such as a thermally conductive paste or a gap pad, between thefirst planar heat transfer area 23 of the core and the planar surface 14of the housing 12. Similarly, between the second planar heat transferarea 23′ of the core and the cap 19 a further thermally conductive layer21 is disposed. The two thermally conductive layers 21, implemented asgap pads for example, therewith improve the heat dissipation in theupper and lower regions of the core and serve for the secure hold of thecore even in the presence of customarily occurring vibrations in arefrigerant compressor of a motor vehicle.

The core can, alternatively, be disposed, for example, with its firstconvex heat transfer area 23 on a concave surface 14 of housing 12. Thesecond heat transfer area 23 can also be implemented convex or planar.If the second heat transfer area 23 is implemented convex, a concaveregion is provided in the cap to receive the core and to hold itsecurely. If the second heat transfer area 23 is implemented planar, inthe cap a region for the heat transfer area 23 is also implementedplanar.

In the example depicted in FIG. 4 the winding of choke 4, 5 is disposedin the circuit board 18. In the multi-layer circuit board 18 coppertracks in several planes, which run in the interior of the core and areelectrically interconnected, are utilized for forming the winding in thecore. For this purpose, in the circuit board 18 appropriate notches areprovided in order to be able to arrange the core, comprised of two coreparts 10, about the portion of the circuit board 18 which represents thewinding of choke 4, 5. The portion of the circuit board 18 thatrepresents the winding of choke 4,5 or the bus bar, is denoted in FIG. 4by the reference number 11.

On the circuit board 18 are additionally located the capacitors 6, 7, 8and 9 associated with the passive EMC filter 1, as well as thecomponents associated with the inverter 2.

As is shown in FIG. 3, the winding of choke 4, 5 can alternatively alsobe implemented in the form of a U-shaped bus bar 11.

In the lower region of the core the heat 20 can be dissipated directlyfrom the core across thermally conductive layer 21 into the cooledhousing 12 of the refrigerant compressor. In the upper region of thecore the heat 20 is dissipated into the cap 19 and across it to thehousing 12. In this embodiment, consequently, improved cooling of thecore of a choke 4, 5 in a passive EMC filter 1 can also be achieved.

To secure the cap 19 on the housing 12 of the refrigerant compressor, atleast two fasteners 22 can be applied which serve for the safesecurement of cap 19 on housing 12 and also allow opening the cap formaintenance and repair work.

LIST OF REFERENCE NUMBERS

-   1 EMC filter-   2 Inverter-   3 Input (HV+/HV−)-   4 First choke L₁-   5 Second choke L₂-   6 First capacitor C₁-   7 Second capacitor C₂-   8 Third capacitor C₃-   9 Fourth capacitor C₄-   10 Core parts of choke-   11, 11′ Bus bar-   12 Housing-   13 Coolant-   14 Surface-   15 Bracket-   16 Plate washer-   17 Bolt-   18 Circuit board-   19 Cap-   20 Heat-   21 Thermally conductive layer (gap pad)-   22 Fasteners-   23, 23′ Heat transfer area

The invention claimed is:
 1. An electromagnetic compatibility (EMC)filter connected to an inverter of a refrigerant compressor andcomprising at least one choke with a core and several capacitors,wherein the core of the choke is developed having one or two core parts,wherein at least one first planar or convex heat transfer area isdisposed on an outside of the core, wherein the core with this firstplanar or convex heat transfer area is disposed on a housing of therefrigerant compressor, wherein the housing in the region of the firstplanar or convex heat transfer area is implemented planar or concave;wherein as the winding of the choke in the core a bus bar is disposed;and wherein the bus bar is electrically conducting connected to thecircuit board of the inverter and wherein the capacitors of the passiveEMC filter are disposed on the circuit board.
 2. An EMC filter as inclaim 1, wherein a second planar or convex heat transfer area isdisposed on the outside of the core, and wherein the second planar orconvex heat transfer area is disposed oriented in parallel or oppositelyto the first planar or convex heat transfer area.
 3. An EMC filter as inclaim 1, wherein a bracket is disposed on a second planar or convex heattransfer area of the core and wherein the bracket is connected with thehousing.
 4. An EMC filter as in claim 1, wherein a cap is disposed on asecond planar or convex heat transfer area of the core, wherein the capis connected with the housing, and wherein the cap in the region of thesecond planar or convex heat transfer area is implemented planar orconcave.
 5. An EMC filter according to claim 1, wherein a thermallyconductive layer is disposed between the first planar or convex heattransfer area and the housing.
 6. An EMC filter according to claim 1,wherein a thermally conductive layer is disposed between the secondplanar or convex heat transfer area and the bracket or the cap.
 7. AnEMC filter according to claim claim 5, wherein a thermally conductivepaste or a gap pad is disposed as the thermally conductive layer.
 8. AnEMC filter according to claim 1, wherein plate washers are disposed on abracket plate, wherein the plate washers include holes for screws, boltsor adjusting pins; and wherein the bracket and the plate washers arebolted or secured on the housing with the screws, the bolts or theadjusting pins.
 9. An EMC filter as in claim 2, wherein a cap isdisposed on the second planar or convex heat transfer area of the core,and wherein the cap is connected with the housing, wherein the cap inthe region of the second planar or convex heat transfer area isimplemented planar or concave.
 10. An EMC filter according to claim 2,wherein a thermally conductive layer is disposed between the firstplanar or convex heat transfer area and the housing.
 11. An EMC filteraccording to claim 3, wherein a thermally conductive layer is disposedbetween the first planar or convex heat transfer area and the housing.12. An EMC filter according to claim 4, wherein a thermally conductivelayer is disposed between the first planar or convex heat transfer areaand the housing.
 13. An EMC filter as in claim 2, wherein a bracket isdisposed on a second planar or convex heat transfer area of the core andwherein the bracket is connected with the housing.
 14. An EMC filter asin claim 2, wherein a bracket is disposed on a second planar or convexheat transfer area of the core and wherein the bracket is connected withthe housing.
 15. An EMC filter as in claim 4, wherein a bracket isdisposed on a second planar or convex heat transfer area of the core andwherein the bracket is connected with the housing.
 16. An EMC filteraccording to claim 4, wherein a thermally conductive layer is disposedbetween the first planar or convex heat transfer area and the housing.17. An EMC filter according to claim 3, wherein plate washers aredisposed on a bracket plate, wherein the plate washers include holes forscrews, bolts or adjusting pins; and wherein the bracket and the platewashers are bolted or secured on the housing with the screws, the boltsor the adjusting pins.
 18. An EMC filter according to claim 4, whereinplate washers are disposed on a bracket plate, wherein the plate washersinclude holes for screws, bolts or adjusting pins; and wherein thebracket and the plate washers are bolted or secured on the housing withthe screws, the bolts or the adjusting pins.
 19. An EMC filter accordingto claim 5, wherein plate washers are disposed on a bracket plate,wherein the plate washers include holes for screws, bolts or adjustingpins; and wherein the bracket and the plate washers are bolted orsecured on the housing with the screws, the bolts or the adjusting pins.20. An EMC filter according to claim 6, wherein plate washers aredisposed on a bracket plate, wherein the plate washers include holes forscrews, bolts or adjusting pins; and wherein the bracket and the platewashers are bolted or secured on the housing with the screws, the boltsor the adjusting pins.